Description:
------------
When using the SOAP client with a WSDL that defines a portion of the schema with elementFormDefault="qualified", but without a URI for the namespace, using _soapCall() fails for any request that contains complex elements from that portion of the schema. It appears that direct children are handled correctly (left in the default namespace), but further ancestors are being prefixed with a namespace that has a blank URI. This is conjecture, as all I can see is a soapfault of Bad Request.

Test script:
---------------
<?php
$_WsdlUri='http://169.132.165.178/b2bapi/b2bservice.asmx?WSDL';

$Server=new SoapClient($_WsdlUri, array('trace' => true));

$sessionstart->UserInfo->UserName = 'user_name';
$sessionstart->UserInfo->Password = 'password';

$result = $Server->__soapCall('SessionStart', array($sessionstart));
print_r($result);

$getproducts->GetProductsRequest->UserInfo->UserName = 'user_name';
$getproducts->GetProductsRequest->UserInfo->Password = 'password';
$getproducts->GetProductsRequest->ClientReferenceData->Service = 'pinless_dialing';

$result = $Server->__soapCall('GetProducts', array($getproducts));
print_r($result);
?>

Expected result:
----------------
SOAP responses (albeit login failures for both in the example above)

Actual result:
--------------
SOAP response for SessionStart, 'BAD REQUEST' error for GetProducts

Replacing the example WSDL with the URI to the following script generates correct behavior:

<?php
$url ='http://169.132.165.178/b2bapi/b2bservice.asmx?WSDL';
$wsdl = file_get_contents($url);
$pattern = '#<s:schema elementFormDefault="qualified">#';
$wsdl = preg_replace($pattern, '<s:schema>', $wsdl);
print ($wsdl);
?>